5 Soil Cycle

SOIL: SOIL By: David Bennett, Bianca Botta, Katie Heineman, Rachel O’Reilly, and Theresa Won
What is soil?: What is soil? Direct and indirect source of food for much of life on earth Natural resource Home to many animals Contains mineral and organic particles, plant and animal matter, and air and water Contents change constantly
Which Sphere?: Which Sphere? Soil is also called the “Pedosphere” Pedology= the study of soil Lithosphere(rock and other geologic material sphere) is where soil is Soil is an integrator for all the other geospheres
COMPOSITION: COMPOSITION Soil particles with water and air in the space between Pore spaces-where plants and animals live MINERALS PLANT AND ANIMAL MATTER WATER AIR
CHARACTERISTICS OF SOIL: CHARACTERISTICS OF SOIL Soil formation differs throughout a body of soil and as a result, the soil develops layers- soil horizons -Can be thick, thin, differ between horizons, boundaries can be distinct or barely noticeable Pedologists describe soils by the characteristics of the soil horizons: -color -texture -structure -chemical conditions
HORIZONS: HORIZONS 3 MAJOR HORIZONS: -upper two: A & B horizons Lowest: C Horizon Most highly developed layers A= top soil C= subsoil,exposed to little weathering & resembles compostition of parent material
SOIL LAYERS: SOIL LAYERS O Horizon - The top layer of soil which is mainly made up of humus and leaf litter. A Horizon – dark colored layer named topsoil. This is where seeds germinate and plant roots grow. Made up of humus and mineral particles. E Horizon – layer which is light in color mostly made up of sand and silt. lost most of its minerals and clay as water drips through the soil . B Horizon - Also called the subsoil. Contains clay and mineral deposits (like iron, aluminum oxides, and calcium carbonate) that come from mineralized water above. C Horizon – called Regolith. Consists of slightly broken-up bedrock. Plant roots do not reach this area and there is organic material found in this layer. R Horizon - The un-weathered rock layer that is beneath all the other layers.
SOIL STRUCTURE: SOIL STRUCTURE Granular Blocky Prismatic Columnar Single Grained Massive Platy
COLOR: Can range from dark brown & black to yellow & red Helps Pedologists estimate the amounts of air, organic matter,water, & elements in the soil EX: Red may show that iron compounds are present in the soil COLOR
TEXTURE: TEXTURE Depends on size of mineral particles Sands-largest particles, seen & felt, promotes drainage best Silts-just large enough to be seen Clay-microscopic Divided into textural classes according to the amount of sand, silt, and clay in the soil Texture helps show how well water drains from a soil
CHEMICAL CONDITIONS: CHEMICAL CONDITIONS Alkaline, acid or neutral Acid and alkaline influence biological and chemical processes present in soil Highly acidic can harm plants Most soils are chemically neutral & support biological and chemical processes Cation exchange-process by which green plants obtain nutrients -> supported in neutral soils
SOIL pH: SOIL pH pH measures how acidic or basic something is Soil solution pH is important because the solution contains nutrients plants need to function The pH of a soil solution can determine what kind of plant can be planted in that soil
How Soil is formed: How Soil is formed Soils are constantly being formed and destroyed. Soil formation varies according to the following environmental factors: -Kinds of parent material, climate, land surface features and plants & animals
Parent Material: Parent Material The rocks and other non-organic matter that serve as the foundation of soil. Through a process called weathering the parent material breaks down and thereby helps determine the kinds of mineral particles found in the soil. There are two types of weathering…
Physical Disintegration and Chemical Decomposition: Physical Disintegration and Chemical Decomposition Physical disintegration- caused by ice, rain, and other physical forces. Chemical Decomposition- breakdown of the rock’s chemical structure resulting in the formation of minerals which then become available to plants as nutrients. This effects the kinds of plants found growing in the soil.
Physical Disintegration Chemical Decomposition: Physical Disintegration Chemical Decomposition
Effects of Climate: Effects of Climate Effects amount of physical and chemical activity, as well as the kinds and rates of weathering. Hot Regions: encourage chemical decomposition, promote decay Cold Regions: physical disintegration more prominent, slow rate of decay. As a result, cold regions often have shallower, less developed soil.
Wind Erosion: Wind Erosion Occurs in mostly flat, dry areas and moist sandy soils along bodies of water
Wind Erosion: Wind Erosion Hazard potential for erosion is determined by the surface texture. For example, mucks and sand are susceptible, while clay is not.
Wind Erosion: Wind Erosion Wind erosion removes soil and natural vegetation, also causing dryness and deterioration of the soil structure
Effects of Land Surface Features: Effects of Land Surface Features Influences amount of soil development in an area Land near water exposed to more topsoil erosion, which exposes new rock to weathering Soils on slopes erode more rapidly than those on flat areas
Effects of Plants and Animals: Effects of Plants and Animals Organisms in soil and organic material help soil development and protect it from erosion Death and decay of plants and animals add organic material to soil which helps the soil support new organisms Soils that are covered with vegetation and have large amounts of organic material are not easily eroded
WORMS!: WORMS! Without worms, we wouldn’t be able to have healthy soil that enables us to grow plants.
WORMS!: WORMS! Worms are beneficial in many ways: -help increase air and water that gets into the soil -break down organic matter, such as leaves or grass, into things that plants can use
WORMS!: WORMS! More benefits: -They leave behind castings (scat) that make a very good fertilizer -They help turn the soil, bringing the organic matter from the top down, mixing it with the soil below
BACTERIA: BACTERIA A teaspoon of soil contains between 100 million and 1 billion bacteria which is as much mass as two cows per acre Bacteria convert energy in soil organic matter into forms useful to the rest of the organisms in the soil food web. Decomposers break down pesticides and pollutants in soil Decomposers are especially important in retaining nutrients in their cells which prevents the loss of nutrients from roots Some bacteria affect water movement by producing substances that help bind soil particles Bacteria alter the soil environment so much that it will favor certain plant communities over others
BACTERIA : BACTERIA
Twelve Soil Orders: Twelve Soil Orders Soil taxonomy is a way of classifying soil Soil is placed into 12 different categories known as soil orders
Gelisols: Gelisols Soils of extremely cold climates that contain permafrost within the first two meters of the surface Covers about 8.6% of the Earth’s land in ice-free zones Have the ability to store large quantities of organic carbon Divided into three suborders: histels, turbels, and orthels
Histosols: Histosols Composed mainly of organic materials Limited for engineering use; can be used to mine for fuel and horticultural products Has 4 suborders: folists, fibrists, sabrists, and hemists
Spodosols: Spodosols Acid soils that have a subsurface covered with accumulated humus that also contains aluminum and iron Most commonly found in forest and in humid climates In order to be cultured agriculturally, lime must be added 4 suborders: aquods, cyrods, humods, & orthods
Andisols: Andisols Soils that are a result of volcanic ashes Has the ability to hold large amounts of water and phosphorus Can be found the least out of all the soil orders on earth 7 suborders: aquands, cyrands, torrands, xerands, vitrands, ustands, & udands
Oxisols: Oxisols Highly weathered soils that are most commonly found in tropical regions Contain many minerals and are abundant in iron and aluminum 5 suborders: Aquox, Torrox, Ustox, Perox, and Udox
Vertisols: Vertisols Clay rich soils; shrinks and swells with changes in moisture content Size changes renders basically obsolete for engineering purposes 6 suborders: aquerts, cryerts, xererets, torrerts, usterts, and uderts
Aridisols: Aridisols Arid region soils that show subsurface horizon development Used for range, wildlife, and recreation; due to the dry climate it exists in, it cannot be used for agricultural purposes 7 suborders: cyrids, salids, durids, gypsids, argids, calcids, and cambids
Ultisols: Ultisols Acid forest soils with low fertility that can be found in the humid and tropic regions of the world; in the U.S. they are the “red clay” soils Produces forests because of the good climate conditions it is usually found in 5 suborders: Aquults, Humults, Udults, Ustults, and Xerults
Mollisols: Mollisols Soils found in grassland ecosystyems and has a thick, dark surface horizon The surface is very fertile aka mollic epipedon, which is a result of the organic materials from plant roots Very useful for agriculture and can be found mainly on prairies 7 suborders: Albolls, Aquolls, Rendolls, Cryolls, Xerolls, Ustolls, and Udolls
Alfisols: Alfisols Soils found in humid regions of the world that are fertile and can be used for agricultural purposes Support about 17% of the world‘s population 5 suborders:Aqualfs, Cryalfs, Udalfs, Ustalfs, and Xeralfs
Inceptisols: Inceptisols Lacks features that are found in the other soils Found in mountain areas Used for forestry, recreation, and watershed 6 suborders: Aquepts, Anthrepts, Cryepts, Ustepts, Xerepts, and Udepts
Entisols: Entisols All soils that are not categorized with the other 12 orders Very diverse soils that can be found in rocky settings or large river valleys 5 suborders: Aquents, Arents, Psamments, Fluvents, and Orthents
SOIL CONSERVATION: SOIL CONSERVATION Farm, grazing, and forestland soil give us many products we use however, it is important to conserve How farmers conserve the soil: -maintain high levels of nutrients -plow under certain green plants -add fertilizers -rotate crops to prevent parasitical plants -plant in ways to control erosion If land is overgrazed, it decreases plant life and erosion occurs Foresters help conserve soil by adding parts of trees on the forest floor which adds organic matter
BIBLIOGRAPHY: BIBLIOGRAPHY “Soil layers.” http://www.enchantedlearning.com/geology/soil/ 17 Sept 2004 “NRCS: The Soil Biology Primer.” http://soils.usda.gov/sqi/soil_quality/soil_biology/bacteria.html 16 Sept 2004 “The Order of Soil.” http://soils.ag.uidaho.edu/soilorders/ 16 Sept 2004 “Soil.” Worldbook Multimedia Encyclopedia. 2003 ed. “You Can’t Live Without Me.” http://images.google.com/imgres?imgurl=http://www.urbanext.uiuc.edu. 16 Sep 2004.
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